Double-sided tablet presses are commonly used in the pharmaceutical industry for making tablets. Their configuration is well known. Typically, they comprise a rotor having dies located along its periphery. The rotor rotates through first and second compression zones. In each compression zone, powder is fed to dies, optionally the powder is precompressed and then compressed within the dies, and finally finished tablets are ejected from the press. Because double-sided tablet presses contain two compression zones, with each revolution of the rotor two sets of tablets are made. The tablets are ejected from opposite sides of the press at first and second tablet ejection zones. The ejected tablets are conventionally transferred away in bulk by an ejection chute leading to a collection container such as a drum or hopper.
Commonly assigned, copending U.S. patent application Ser. No. 09/967,414, the disclosure of which is incorporated herein by reference, discloses a transfer device capable of handling substrates such as tablets having a high degree of friability and softness. It is a rotating device comprising a plurality of transfer units attached to a flexible conveying means, such as a belt. It is preferably used for transferring substrates within a continuous process from one operating unit to another, for example from a compression apparatus to a coating apparatus. The flexible conveying means follows a path from the first operating unit to the second operating unit. The velocity and positions of the transfer units are synchronized with the operating units to which it is coupled, so that substrates can be smoothly captured from the first operating unit and released to the second operating unit. The transfer units comprise retainers for holding the substrates. The retainers are preferably flexible and constructed from an elastomeric material. In a preferred embodiment, the retainers are circular and comprise segmented fingers of elastomeric material.
Applicants have now designed a transfer device having transfer units comprising inner and outer, side by side retainers that sequentially rather than simultaneously capture substrates. The device may be used to transfer tablets or other substrates, preferably from a rotary, double-sided tablet press to a second location. The transfer units are mounted on a flexible conveying means that travels along a path coincident with those portions of the tablet press where tablets are ejected. In one embodiment, the transfer units are adapted to receive first tablets at a first substrate receiving station of the apparatus located proximal to the first tablet ejection zone of the tablet press, and adapted to receive second tablets at a second substrate receiving station located proximal to the second tablet ejection zone of the tablet press.